1. Field of the Invention
The present invention relates to a weather strip having a molded portion and to a manufacturing method therefor.
2. Description of the Related Art
Hitherto, a weather strip is attached to an opening portion or along a door peripheral edge of a vehicle, such as an automobile. When this kind of a weather strip is manufactured, an extrusion portion is formed like an elongated one by a publicly known extrusion molding method. Then, in a state in which an end part of the extrusion portion is set in a mold apparatus for molding a molded portion, the molded portion is continuously and connectedly molded to an end surface of the extrusion portion.
The mold apparatus used for connectedly molding the molded portion comprises a stationary mold, plural movable molds and a core mold. The core mold comprises a core body for forming a hollow portion, and also comprises an extending plate extending from the core body. When the molded portion is molded, first, an end portion of the extrusion portion having already been molded by a publicly known extrusion molding method is set in the core body by being fitted thereinto. Thus the extrusion portion is attached to the mold apparatus. Subsequently, each of the molds is disposed at a predetermined place and clamped. At this moment, a cavity for molding a molded portion is formed by using each of the molds. Then, unvulcanized rubber is injected and filled into the cavity through a gate (not shown). Subsequently, unvulcanized rubber is vulcanized. Then, each of the molds is opened. A product obtained by integrating the core mold with the vulcanized rubber (or molded portion precursor) is taken out therefrom. At that time, a slit is formed in the molded precursor owing to the presence of the extending plate.
Thus, the molded portion precursor having a hollow portion is obtained by taking the core body from the slit. Thereafter, opposite opening faces of the slit are bonded by adhesive at plural places. Thus, the molded portion is obtained. That is, a weather strip, in which this molded portion is integral with the extrusion portion, is obtained.
However, hitherto, anticipated design has been performed so that the molded portion precursor is molded to be wider than the extrusion portion by width of the slit so as to bond the opening faces of the slit. An operation of bonding the opening faces indispensably needs a step of compressing and holding the molded portion precursor in the direction of width thereof for a predetermined time in a state in which the adhesive is applied thereon. This results in a fear of increase in the number of working manhours, increase in production cost, and reduction in productivity. Additionally, when the opening faces of the slit are bonded directly to each other, width of a mounting base portion is liable to be uneven. Consequently, there has been a fear of drawbacks, such as reduction in sealability of the molded portion.
In recent years, there has appeared a weather strip having a blocking piece, instead of bonding the opening faces directly to each other, so as to counteract the drawbacks (see, for example, JP-A-6-305372).
However, the weather strip described in JP-A-6-305372 is configured so that the blocking piece is simply turned and assembled to the mounting base portion. Thus, this weather strip indispensably needs a step of bonding the blocking piece with adhesive to the mounting base portion. Also, it is difficult to hold bonded parts until the adhesive dries. Consequently, there has been a fear that the bonded parts may be detached from each other by a restoring force of the blocking piece, and that the slit may be opened.